The fawning and pointedly non-ironic softball interviews (sorry, Conan) with newly-engaged Seth Rogan, on hand to tout the January release of “Green Hornet” – not to mention a perky Lea Michele from Fox’s “Glee” who pouted about how misunderstood her sexy GQ photo shoot was – were, if anything, a breath of stale air. While certainly not awful, the very “conventionalness” of the shows certainly don’t live up to the hype leading up to the return of "Team Coco."

Mr. O'Brien's shows this week are “perfectly acceptable presentations of the genre,” says Robert Thompson, founder of the Bleier Center for Television and Popular Culture at Syracuse University, in a typical underwhelming review. Do they raise questions about the future of the late-night talk show? Sure, say plenty of media-watchers, including the very celebrity guests who are the bread and butter of these shows. As actor David Spade put it in a tweet Wednesday touting his appearance on “The Tonight Show”: "on leno this evening. thinking of dumb stuff to chat about. tune in if out of sominex.”

The format is not the problem, says Benjamin Alba, author of "Inventing Late Night: Steve Allen and the Original Tonight Show." "Despite evolving viewing trends, the late-night talk/variety genre remains the only nighttime genre that has survived, and usually flourished, over the past five decades,” he says via email. Other formats have come and gone, he points out, such as drama anthologies, musical-variety shows, dramatic miniseries, and Westerns. Even sitcoms today don't command the stature they once did, he notes.

But, he adds, “as creator and first host of the "Tonight" show, Steve Allen invented the grammar of late night, which, with a few variations, remains intact in late night today: witty host, live audience, opening monologue, home-base desk, celebrity chats, comedy sketches, wild stunts, goofing around with the band leader, and visiting regular folks in the audience.”

The problem today lies mostly with the hosts, agrees Mr. Thompson, who points out that Jay Leno, David Letterman, and now Conan O'Brien are all getting stale. “They are no longer the young turks they once were,” he says.

Others suggest both the form and the folks who inhabit it are headed for history. New-media expert Paul Levinson points first of all to the fairly precipitous ratings fall-off, noting that both Jay Leno and David Letterman slumped to just above a million viewers apiece in October, a number that Comedy Central’s Jon Stewart bested with 1.3 million viewers in the most-coveted 18-to 49 demographic. Says Mr. Levinson, “nobody below the age of 60 is really tuning into these shows anymore.” Rather, says the author of “New New Media,” they are getting their entertainment from the Internet, their mobile phones, and other devices at all times of the day.”

Beyond that, there is the inherently restrictive nature of the broadcast medium itself, says sociologist Alexander Riley, author of “Impure Play.” Truly “transgressive” behavior does not sit well with the commercial interests behind most of the late-night shows. He points to the appearance in the 1970s of the Sex Pistols on a British talk show. The band members cursed the show’s host and generally flayed the entirety of middle-class British life. The ruckus that ensued went all the way up to the Queen. While hosts such as O’Brien like to suggest they are wacky and out-of-the-box players, in reality, we should not expect “truly transformative behavior” from mainstream commercial media, he says.

Rather, says marketing strategist Susan Harrow, what we will see in the future is less format experimentation and hosts going wacky, but more brand extensions. She points to Web clips and Jon Stewart's recent Washington rally as examples of this already underway. The upcoming simulcast of a Glenn Beck performance to 500 movie theaters nationwide is another example, she says, adding, “people want the excitement of getting out of the studio, but they still want the intimacy of the talk show experience.”